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  • 151.
    Lundström, Linda
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Venkataraman, Abinaya Priya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lewis, Peter R.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Spatiotemporal contrast sensitivity in the 10 degrees visual field2016Inngår i: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, nr 12Artikkel i tidsskrift (Fagfellevurdert)
  • 152.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Phase-Contrast X-Ray Carbon Dioxide Angiography2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Phase-contrast x-ray imaging is an emerging technology, which allows for imaging of smaller features than conventional absorption-based x-ray imaging, with lower radiation dose. Instead of the attenuation that is normally used in x-ray imaging, it utilizes the phase shift introduced by an object to the transmitted x-rays. This phase shift can change the directions of the x-rays slightly, which can be measured in a few different ways. Propagation-based phase contrast, which is the method most used in this Thesis, detects these deviations using a high-resolution imaging detector at a distance from the sample. This Thesis describes how phase-contrast x-ray imaging can be used to image the internal structures of small animals like mice and rats. A technique for imaging of very small blood vessels has been developed and analyzed. By injecting a gas, such as carbon dioxide, into the vascular system, blood vessels down to 8 µm in diameter have been visualized. This is considerably smaller than the 50 µm vessels that can be imaged using iodine-based contrast agents at radiation doses compatible with living animals. A recently invented type of x-ray source, based on a jet of liquid metal as electron-beam target, has been used and further developed for the imaging purposes of this Thesis. Such metal-jet x-ray sources provide very high x-ray flux for the small x-ray spot sizes at which they operate, something that has been crucial for the quality of the phase-contrast images acquired.

  • 153.
    Lundström, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Scott, L.
    Westermark, U. K.
    Wilhelm, M.
    Henriksson, M. Arsenian
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    X-ray phase-contrast CO2 angiography for sub-10 mu m vessel imaging2012Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 57, nr 22, s. 7431-7441Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    X-ray in-line phase contrast has recently been combined with CO2 angiography for high-resolution small-animal vascular imaging at low radiation dose. In this paper we further investigate the potential and limitations of this method and demonstrate observation of vessels down to 8 mu m in diameter, considerably smaller than the 60 mu m previously reported. Our in-line phase-contrast imaging system is based on a liquid-metal-jet-anode x-ray source and utilizes free-space propagation to convert phase shifts, caused by refractive index variations, into intensity differences. Enhanced refractive index variations are obtained through injection of CO2 gas into the vascular system to replace the blood. We show rat-kidney images with blood vessels down to 27 mu m in diameter and mouse-ear images with vessels down to 8 mu m. The minimum size of observable blood vessels is found to be limited by the penetration of gas into the vascular system and the signal-to-noise ratio, i.e. the allowed dose. The diameters of vessels being gas-filled depend on the gas pressure and follow a simple model based on surface tension. A theoretical signal-to-noise comparison shows that this method requires 1000 times less radiation dose than conventional iodine-based absorption contrast for observing sub-50 mu m vessels.

  • 154.
    Lundström, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per A. C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Scott, L.
    Brismar, H.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    X-ray phase contrast for CO2 microangiography2012Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 57, nr 9, s. 2603-2617Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate a laboratory method for imaging small blood vessels using x-ray propagation-based phase-contrast imaging and carbon dioxide (CO2) gas as a contrast agent. The limited radiation dose in combination with CO2 being clinically acceptable makes the method promising for small-diameter vascular visualization. We investigate the possibilities and limitations of the method for small-animal angiography and compare it with conventional absorption-based x-ray angiography. Photon noise in absorption-contrast imaging prevents visualization of blood vessels narrower than 50 mu m at the highest radiation doses compatible with living animals, whereas our simulations and experiments indicate the possibility of visualizing 20 mu m vessels at radiation doses as low as 100 mGy. Experimental computed tomography of excised rat kidney shows blood vessels of diameters down to 60 mu m with improved image quality compared to absorption-based methods. With our present prototype x-ray source, the acquisition time for a tomographic dataset is approximately 1 h, which is long compared to the 1-20 min common for absorption-contrast micro-CT systems. Further development of the liquid-metal-jet microfocus x-ray sources used here and high-resolution x-ray detectors shows promise to reduce exposure times and make this high-resolution method practical for imaging of living animals.

  • 155.
    Lundström, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Scott, L.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    X-ray phase contrast angiography using CO 2 as contrast agent2012Inngår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE, SPIE - International Society for Optical Engineering, 2012, Vol. 8313, s. 83135J-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate the possibility of using x-ray in-line phase-contrast imaging with gaseous carbon dioxide as contrast agent to visualize small blood vessels. These are difficult to image at reasonable radiation doses using the absorption of conventional iodinated contrast agents. In-line phase contrast is a method for retrieving information on the electron density of the sample as well as the absorption, by moving the detector away from the sample to let phase variations in the transmitted x-rays develop into intensity variations at the detector. Blood vessels are normally difficult to observe in phase contrast even with iodinated contrast agents as the density difference compared to most tissues is small. Carbon dioxide is a clinically accepted x-ray contrast agent. The gas is injected into the blood stream of patients to temporarily displace the blood in a region and thereby reduce the x-ray absorption in the blood vessels. This gives a large density difference which is ideal for phase-contrast imaging. We demonstrate the possibilities of the method by imaging the arterial system of a rat kidney injected with carbon dioxide. Vessels down to 23 ÎŒm in diameter are shown. The method shows potential for live small-animal imaging.

  • 156.
    Lundström, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Westermark, U. K.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Small-Animal microangiography using phase-contrast X-ray imaging and gas as contrast agent2014Inngår i: Medical Imaging 2014: Physics of Medical Imaging, SPIE - International Society for Optical Engineering, 2014, s. 90331L-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We use propagation-based phase-contrast X-ray imaging with gas as contrast agent To visualize The microvasculature in small animals like mice and rats. The radiation dose required for absorption X-ray imaging is proportional To The minus fourth power of The structure size To be detected. This makes small vessels impossible To image at reasonable radiation doses using The absorption of conventional iodinated contrast agents. Propagation-based phase contrast gives enhanced contrast for high spatial frequencies by moving The detector away from The sample To let phase variations in The Transmitted X-rays develop into intensity variations at The detector. Blood vessels are normally difficult To observe in phase contrast even with iodinated contrast agents as The density difference between blood and most Tissues is relatively small. By injecting gas into The blood stream This density difference can be greatly enhanced giving strong phase contrast. One possible gas To use is carbon dioxide, which is a clinically accepted X-ray contrast agent. The gas is injected into The blood stream of patients To Temporarily displace The blood in a region and Thereby reduce The X-ray absorption in The blood vessels. We have shown That This method can be used To image blood vessels down To 8 μm in diameter in mouse ears. The low dose requirements of This method indicate a potential for live small-Animal imaging and longitudinal studies of angiogenesis.

  • 157.
    Lundström, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Westermark, Ulrica K.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Arsenian Henriksson, Marie
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    X-ray phase contrast with injected gas for tumor microangiography2014Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 59, nr 11, s. 2801-2811Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that the microvasculature of mouse tumors can be visualized using propagation-based phase-contrast x-ray imaging with gas as the contrast agent. The large density difference over the gas-tissue interface provides high contrast, allowing the imaging of small-diameter blood vessels with relatively short exposure times and low dose using a compact liquid-metal-jet x-ray source. The method investigated is applied to tumors (E1A/Ras-transformed mouse embryonic fibroblasts) grown in mouse ears, demonstrating sub-15-mu m-diameter imaging of their blood vessels. The exposure time for a 2D projection image is a few seconds and a full tomographic 3D map takes some minutes. The method relies on the strength of the vasculature to withstand the gas pressure. Given that tumor vessels are known to be more fragile than normal vessels, we investigate the tolerance of the vasculature of 12 tumors to gas injection and find that a majority withstand 200 mbar pressures, enough to fill 12-mu m-diameter vessels with gas. A comparison of the elasticity of tumorous and non-tumorous vessels supports the assumption of tumor vessels being more fragile. Finally, we conclude that the method has the potential to be extended to the imaging of 15 mu m vessels in thick tissue, including mouse imaging, making it of interest for, e.g., angiogenesis research.

  • 158.
    Makita, M.
    et al.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Vartiainen, I.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Mohacsi, I.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.;LOrme Merisiers, Synchrotron SOLEIL, F-91190 Saint Aubin, France..
    Caleman, C.
    Deutsch Elektronen Synchrotron DESY, CFEL, D-22667 Hamburg, Germany.;Uppsala Univ, Dept Phys & Astron, SE-751 Uppsala, Sweden..
    Diaz, A.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Jönsson, Henrik Olof
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Department of Physics and Astronomy, Uppsala University, SE-751 24, Uppsala, Sweden.
    Juranic, P.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Medvedev, N.
    Czech Acad Sci, Inst Phys, Prague 18221 8, Czech Republic.;Czech Acad Sci, Inst Plasma Phys, Prague 18200 8, Czech Republic..
    Meents, A.
    Deutsch Elektronen Synchrotron DESY, CFEL, D-22667 Hamburg, Germany..
    Mozzanica, A.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Opara, N. L.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.;Univ Basel, C CINA Biozentrum, CH-4058 Basel, Switzerland..
    Padeste, C.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Panneels, V.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Saxena, V.
    Deutsch Elektronen Synchrotron DESY, CFEL, D-22667 Hamburg, Germany.;Bhat, Inst Plasma Res, Gandhinagar 382428, India..
    Sikorski, M.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Song, S.
    Vera, L.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Willmott, P. R.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Beaud, P.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Milne, C. J.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Ziaja-Motyka, B.
    Deutsch Elektronen Synchrotron DESY, CFEL, D-22667 Hamburg, Germany.;Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    David, C.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Femtosecond phase-transition in hard x-ray excited bismuth2019Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikkel-id 602Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The evolution of bismuth crystal structure upon excitation of its A(1g) phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal at high intensities (similar to 10(14) W/cm(2)). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300 fs, i.e. faster than one oscillation period of the A(1g) mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to plasma formation.

  • 159.
    Malek Khachatourian, Adrine
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM. Iran University of Science and Technology, Iran .
    Golestani-Fard, Farhad
    Sarpoolaky, Hossein
    Vogt, Carmen
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Toprak, Muhammet S.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Microwave assisted synthesis of monodispersed Y2O3 and Y2O3:Eu3+ particles2015Inngår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, nr 2, s. 2006-2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monodisperse spherical Y2O3 and Y2O3:Eu3+ nanocrystalline particles with particle size between 100 nm and 350 nm were successfully prepared by microwave assisted urea precipitation method followed by a thermochemical treatment. Fast microwave heating, controlled decomposition of urea and burst nucleation of metal ions in aqueous solution led to the formation of non-aggregated spherical particles with narrow size dispersion. The particle size and size dispersion was controlled by adjusting the urea/metal ions ratio, the metal ions concentration, the reaction time and the temperature. X-ray diffraction (XRD) analysis indicated that the as prepared particles have Y(OH)CO3 composition, which converted to highly crystalline cubic Y2O3 after calcination at temperatures above 600 degrees C. The calcined Y2O3 particles preserved the spherical morphology of the as prepared particles and exhibited polycrystalline structure. The size of the crystallites increased from similar to 8 nm to similar to 37 nm with the increase of the calcination temperature from 500 degrees C to 900 degrees C. In order to transform these nanostructures to luminescent composition, Eu3+ doping has been performed. Y2O3:Eu3+ particles inherited the morphology and polycrystalline structure of the host Y2O3 particles. Photoluminescence (PL) analysis of Y2O3:Eu3+ particles showed a strong red emission peak at 613 nm corresponding to D-5(0)-F-7(2) forced electric dipole transition of Eu3+ ions under UV excitation. All these critical characteristics, and being heavy-metal free, make these particles useful for bioimaging, and display devices.

  • 160.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Multidimensional Ultrasonic Standing Wave Manipulation in Microfluidic Chips2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The use of ultrasonic standing waves for contactless manipulation of microparticles in microfluidic systems is a field with potential to become a new standard tool in lab-on-chip systems. Compared to other contactless manipulation methods ultrasonic standing wave manipulation shows promises of gentle cell handling, low cost, and precise temperature control. The technology can be used both for batch handling, such as sorting and aggregation, and handling of single particles.

    This doctoral Thesis presents multi-dimensional ultrasonic manipulation, i.e., manipulation in both two and three spatial dimensions as well as time-dependent manipulation of living cells and microbeads in microfluidic systems. The lab-on-chip structures used allow for high-quality optical microscopy, which is central to many bio-applications. It is demonstrated how the ultrasonic force fields can be spatially confined to predefined regions in the system, enabling sequential manipulation functions. Furthermore, it is shown how frequency-modulated signals can be used both for spatial stabilization of the force fields as well as for flow-free transport of particles in a microchannel. Design parameters of the chip-transducer systems employed are investigated experimentally as well as by numerical simulations. It is shown that three-dimensional resonances in the solid structure of the chip strongly influences the resonance shaping in the channel.

  • 161.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hultström, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Dynamics of ultrasonic standing wave nodal patterns in a microfluidic chip by acoustic streaming and coupling effects2007Inngår i: Proc. 1st International Congress on Ultrasonics, 2007Konferansepaper (Fagfellevurdert)
  • 162.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hultström, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Elementary manipulation functions for gentle and long-term handling of cells in micro-channels by ultrasonic standing waves2006Inngår i: Proc. 10th Annual European Conference on Micro & Nanoscale Technologies for the Biosciences, 2006Konferansepaper (Fagfellevurdert)
  • 163.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hultström, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Proliferation of adherent cells manipulated by standing wave ultrasound in a microfluidic chip2006Konferansepaper (Annet vitenskapelig)
  • 164.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Rosén, Robert
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Högfeldt, Anna-Karin
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Lärande.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Edström, Kristina
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Lärande. KTH, Skolan för industriell teknik och management (ITM), Lärande.
    En struktur för ökad funktionell kunskap hos studenten från räkneövningar2008Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    En struktur för räkneövningar med syftet att ge studenten ökade funktionella kunskaper och färdigheter i ämnet presenteras. Strukturen är avsedd att aktivera studenten både innan och under en räkneövning. Genom kamraträttning av frivilliga hemuppgifter frikopplade från bonussystem, student-student-diskussioner samt diskussion i helklass antas studenten uppmuntras till djupare lärstrategier och nå en högre taxonominivå inom ämnet.Strukturen utprovas på två studentgrupper; andraårsstudenter på ett civilingenjörsprogram på KTH, samt förstårsstudenter på optikerutbildningen på Karolinska Institutet som läser optikkurser vid KTH. Utvärdering sker under pågående kurs genom enkäter till alla studenterna samt intervjuer av optikerstudenter, samt efter fullgången kurs genom intervjuer av assistenter och ingenjörsstudenter. Resultaten visar att studenterna ställer sig positiva till det nya systemet och anser att det ger dem en djupare nivå av förståelse, att det skapar en mer transparent bild av rättningsprocessen, samt att det ökar interaktionen mellan studenter och skapar en bättre klassrumsmiljö. Deltagandet är stort bland optikerstudenterna, medan ingenjörsstudenterna anser att de har betydligt svårare att hitta tid till hemuppgifterna.

  • 165.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Strååt, Johan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Multidimensional ultrasonic manipulation stabilized by frequency modulation2008Konferansepaper (Annet vitenskapelig)
  • 166.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Svennebring, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Towards spatially confined ultrasonic standing wave fields in a microfluidic chip by microchannel design2007Konferansepaper (Fagfellevurdert)
  • 167.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Svennebring, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic micro-cages: A new approach for manipulation and monitoring of individual cells and for fluid mixing2008Inngår i: 12th International Conference on Miniaturized Systems for Chemistry and Life Sciences - The Proceedings of MicroTAS 2008 Conference, Chemical and Biological Microsystems Society , 2008, s. 1495-1497Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Four designs of ultrasonic microcages are presented together with force field simulations and experimental verification. The microcages enable three-dimensional ultrasonic manipulation of individual microparticles combined with on-line monitoring using high-resolution optical microscopy. The microcages can also be employed as acoustic-streaming-based micromixers. We investigate and compare the force field distributions and streaming patterns in the cages, and we demonstrate concentration, aggregation and positioning of individual particles. The cages can be used for, e.g., studies of interactions between single cells and functionalized particles or pairs of cells in contact only with each other.

  • 168.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Svennebring, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wedge transducer design for two-dimensional ultrasonic manipulation in a microfluidic chip2008Inngår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, s. 095025-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze and optimize the design of wedge transducers used for the excitation of resonances in the channel of a microfluidic chip in order to efficiently manipulate particles or cells in more than one dimension. The design procedure is based on (1) theoretical modeling of acoustic resonances in the transducer-chip system and calculation of the force fields in the fluid channel, (2) full-system resonance characterization by impedance spectroscopy and (3) image analysis of the particle distribution after ultrasonic manipulation. We optimize the transducer design in terms of actuation frequency, wedge angle and placement on top of the chip, and we characterize and compare the coupling effects in orthogonal directions between single- and dual-frequency ultrasonic actuation. The design results are verified by demonstrating arraying and alignment of particles in two dimensions. Since the device is compatible with high-resolution optical microscopy, the target application is dynamic cell characterization combined with improved microfluidic sample transport.

  • 169.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Svennebring, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    A three-dimensional ultrasonic cage for characterization of individual cells2008Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, s. 063901-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate enrichment, controlled aggregation, and manipulation of microparticles and cells by an ultrasonic cage integrated in a microfluidic chip compatible with high-resolution optical microscopy. The cage is designed as a dual-frequency resonant filleted square box integrated in the fluid channel. Individual particles may be trapped three dimensionally, and the dimensionality of one-dimensional to three-dimensional aggregates can be controlled. We investigate the dependence of the shape and position of a microparticle aggregate on the actuation voltages and aggregate size, and demonstrate optical monitoring of individually trapped live cells with submicrometer resolution.

  • 170.
    Manneberg, Otto
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Svennebring, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic microcages for high-resolution characterization of individual cells2008Konferansepaper (Fagfellevurdert)
  • 171. Marcos, S.
    et al.
    Werner, J. S.
    Burns, S. A.
    Merigan, W. H.
    Artal, P.
    Atchison, D. A.
    Hampson, K. M.
    Legras, R.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Yoon, G.
    Carroll, J.
    Choi, S. S.
    Doble, N.
    Dubis, A. M.
    Dubra, A.
    Elsner, A.
    Jonnal, R.
    Miller, D. T.
    Paques, M.
    Smithson, H. E.
    Young, L. K.
    Zhang, Y.
    Campbell, M.
    Hunter, J.
    Metha, A.
    Palczewska, G.
    Schallek, J.
    Sincich, L. C.
    Vision science and adaptive optics, the state of the field2017Inngår i: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 132, s. 3-33Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adaptive optics is a relatively new field, yet it is spreading rapidly and allows new questions to be asked about how the visual system is organized. The editors of this feature issue have posed a series of question to scientists involved in using adaptive optics in vision science. The questions are focused on three main areas. In the first we investigate the use of adaptive optics for psychophysical measurements of visual system function and for improving the optics of the eye. In the second, we look at the applications and impact of adaptive optics on retinal imaging and its promise for basic and applied research. In the third, we explore how adaptive optics is being used to improve our understanding of the neurophysiology of the visual system.

  • 172.
    Martz, Dale H.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Selin, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fogelqvist, Emelie
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Legall, H.
    Blobel, G.
    Seim, C.
    Stiel, H.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    High average brightness water window source for short-exposure cryomicroscopy2012Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, nr 21, s. 4425-4427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Laboratory water window cryomicroscopy has recently demonstrated similar image quality as synchrotron-based microscopy but still with much longer exposure times, prohibiting the spread to a wider scientific community. Here we demonstrate high-resolution laboratory water window imaging of cryofrozen cells with 10 s range exposure times. The major improvement is the operation of a lambda = 2.48 nm, 2 kHz liquid nitrogen jet laser plasma source with high spatial and temporal stability at high average brightness >1.5 x 10(12) ph/(s x sr x mu m(2) x line), i.e., close to that of early synchrotrons. Thus, this source enables not only biological x-ray microscopy in the home laboratory but potentially other applications previously only accessible at synchrotron facilities.

  • 173.
    Meszaros, Johan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Large area zone plate exposure by fixed beam moving stage lithography2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this diploma project the so-called fixed beam moving stage (FBMS) module in the Raith 150 electron beam lithography system has been evaluated for making large area zone plate exposures. The project goal, besides the evaluation of the module, has been to find an exposure recipe for exposing zone plates with diameter up to 500 μm. The zone plates fabricated with this method will be used for synchrotron and x-ray free electron laser applications.

    The thesis starts with a short introduction to zone plate properties and fabrication procedures. Then the work where FBMS exposed zone plates are compared with normal write field exposures of 75 μm diameter zone plates is described. The conclusion is that for these small diameters, major problems with wobbly zones occur for the FBMS patterns. However, for larger diameters the pattern typically looks better. The final result with large area exposures are excellent zone plate patterns with 500 μm diameter and 100 nm outermost zone width. The total exposure time was 2 h 15 min. This relatively short time indicate that it will be practically possible to use the Raith system for these large area exposures.

  • 174.
    Mi, Wujun
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik.
    Karlsson, Staffan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Danielsson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik.
    Nillius, Peter
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik.
    Fabrication of circular sawtooth gratings using focused UV lithography2016Inngår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, nr 3, artikkel-id 035001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AbstractThis paper presents a novel micro-fabrication method using focused ultraviolet (UV) light to manufacture three-dimensional sawtooth structures in ultra-thick negative photoresist to fabricate a novel multi-prism x-ray lens. The method uses a lens to shape the UV beam instead of the photomask conventionally used in UV lithography. Benefits of this method include the ability to manufacture sawtooth structures in free form, for example in circular shapes as well as arrays of these shapes, and in resist that is up to 76 μm thick.To verify the method, initially a simple simulation based on Fourier optics was done to predict the exposure energy distribution in the photoresist. Furthermore, circular sawtooth gratings were manufactured in a 76 μm SU-8 resist. The UV lens was fabricated using electron beam lithography and then used to expose the SU-8 with UV light. This paper details the complete developed process, including pre-exposure with an e-beam and cold development, which creates stable sawtooth structures. The measured profile was compared to the ideal sawtooth and the simulation. The main discrepancy was in the smallest feature size, the sawtooth tips, which were wider than the desired structures, as would be expected by simulation.

  • 175.
    Mohamed, Alaa
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Cairo University, Egypt.
    Nasser, W. S.
    Osman, T. A.
    Toprak, Muhammet
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Muhammed, Mamoun
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Removal of chromium (VI) from aqueous solutions using surface modified composite nanofibers2017Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 505, s. 682-691Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel material composite nanofibers (PAN-CNT/TiO2-NH2) based on adsorption of Cr(VI) ions, was applied. Polyacrylonitrile (PAN) and carbon nanotube (CNTs)/titanium dioxide nanoparticles (TiO2) functionalized with amine groups (TiO2-NH2) composite nanofibers have been fabricated by electrospinning. The nanostructures and the formation process mechanism of the obtained PAN-CNT/TiO2-NH2 composite nanofibers are investigated using FTIR, XRD, XPS, SEM, and TEM. The composite nanofibers were used as a novel adsorbent for removing toxic chromium Cr(VI) in aqueous solution. The kinetic study, adsorption isotherm, pH effect, initial concentration, and thermodynamic study were investigated in batch experiments. The composite nanofibers had a positive effect on the absorption of Cr(VI) ions under neutral and acidic conditions, and the saturated adsorption reached the highest when pH was 2. The adsorption equilibrium reached within 30 and 180 min with an initial solution concentration increasing from 10 to 300 mg/L, and the process can be better described using nonlinear pseudo first than nonlinear pseudo second order model and Intra-particle diffusion. Isotherm data fitted well using linear and nonlinear Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm adsorption model. Thermodynamic study showed that the adsorption process is exothermic. The adsorption capacity can remain up to 80% after 5 times usage, which show good durability performance. The adsorption mechanism was also studied by UV-vis and XPS.

  • 176. Mukherjee, S. P.
    et al.
    Gliga, A. R.
    Lazzaretto, B.
    Brandner, B.
    Fielden, Matthew
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Vogt, Carmen
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Newman, L.
    Rodrigues, A. F.
    Shao, W.
    Fournier, P. M.
    Toprak, Muhammet Sadaka
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Star, A.
    Kostarelos, K.
    Bhattacharya, K.
    Fadeel, B.
    Graphene oxide is degraded by neutrophils and the degradation products are non-genotoxic2018Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, nr 3, s. 1180-1188Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neutrophils were previously shown to digest oxidized carbon nanotubes through a myeloperoxidase (MPO)-dependent mechanism, and graphene oxide (GO) was found to undergo degradation when incubated with purified MPO, but there are no studies to date showing degradation of GO by neutrophils. Here we produced endotoxin-free GO by a modified Hummers' method and asked whether primary human neutrophils stimulated to produce neutrophil extracellular traps or activated to undergo degranulation are capable of digesting GO. Biodegradation was assessed using a range of techniques including Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and mass spectrometry. GO sheets of differing lateral dimensions were effectively degraded by neutrophils. As the degradation products could have toxicological implications, we also evaluated the impact of degraded GO on the bronchial epithelial cell line BEAS-2B. MPO-degraded GO was found to be non-cytotoxic and did not elicit any DNA damage. Taken together, these studies have shown that neutrophils can digest GO and that the biodegraded GO is non-toxic for human lung cells.

  • 177. Munke, Anna
    et al.
    Andreasson, Jakob
    Aquila, Andrew
    Awel, Salah
    Ayyer, Kartik
    Barty, Anton
    Bean, Richard J.
    Berntsen, Peter
    Bielecki, Johan
    Boutet, Sebastien
    Bucher, Maximilian
    Chapman, Henry N.
    Daurer, Benedikt J.
    DeMirci, Hasan
    Elser, Veit
    Fromme, Petra
    Hajdu, Janos
    Hantke, Max F.
    Higashiura, Akifumi
    Hogue, Brenda G.
    Hosseinizadeh, Ahmad
    Kim, Yoonhee
    Kirian, Richard A.
    Reddy, Hemanth K. N.
    Lan, Ti-Yen
    Larsson, Daniel S. D.
    Liu, Haiguang
    Loh, N. Duane
    Maia, Filipe R. N. C.
    Mancuso, Adrian P.
    Muhlig, Kerstin
    Nakagawa, Atsushi
    Nam, Daewoong
    Nelson, Garrett
    Nettelblad, Carl
    Okamoto, Kenta
    Ourmazd, Abbas
    Rose, Max
    van der Schot, Gijs
    Schwander, Peter
    Seibert, M. Marvin
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sierra, Raymond G.
    Song, Changyong
    Svenda, Martin
    Timneanu, Nicusor
    Vartanyants, Ivan A.
    Westphal, Daniel
    Wiedorn, Max O.
    Williams, Garth J.
    Xavier, Paulraj Lourdu
    Yoon, Chun Hong
    Zook, James
    Data Descriptor: Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source2016Inngår i: Scientific Data, E-ISSN 2052-4463, Vol. 3, artikkel-id UNSP 160064Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a wellcharacterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 mu m diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 angstrom ngstrom were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

  • 178.
    Mühlig, Kerstin
    et al.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden. .
    Gañán-Calvo, Alfonso M.
    Andreasson, Jakob
    Larsson, Daniel S. D.
    Hajdu, Janos
    Svenda, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden.
    Nanometre-sized droplets from a gas dynamic virtual nozzle2019Inngår i: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767, Vol. 52, s. 800-808Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reports on improved techniques to create and characterize nometre-sized droplets from dilute aqueous solutions by using a gas namic virtual nozzle (GDVN). It describes a method to measure the size stribution of uncharged droplets, using an environmental scanning ectron microscope, and provides theoretical models for the droplet zes created. The results show that droplet sizes can be tuned by justing the gas and liquid flow rates in the GDVN, and at the lowest quid flow rates, the size of the water droplets peaks at about 120nm. is droplet size is similar to droplet sizes produced by electrospray nization but requires neither electrolytes nor charging of the lution. The results presented here identify a new operational regime r GDVNs and show that predictable droplet sizes, comparable to those tained by electrospray ionization, can be produced by purely chanical means in GDVNs.

  • 179. Nachtrab, F.
    et al.
    Firsching, M.
    Speier, C.
    Uhlmann, N.
    Takman, P.
    Tuohimaa, T.
    Heinzl, C.
    Kastner, J.
    Larsson, Daniel
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildteknik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Berti, G.
    Krumm, M.
    Sauerwein, C.
    NanoXCT: Development of a laboratory nano-CT system2014Inngår i: Proceedings of SPIE - The International Society for Optical Engineering, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The NanoXCT project aims at developing a laboratory nano-CT system for non-destructive testing applications in the micro- and nano-technology sector. The system concept omits the use of X-ray optics, to be able to provide up to 1 mm FOV (at 285 nm voxel size) and down to 50 nm voxel size (at 0.175 mm FOV) while preserving the flexibility of state-of-the-art micro-CT systems. Within the project a suitable X-ray source, detector and manipulation system are being developed. To cover the demand for elemental analysis, the project will additionally include X-ray spectroscopic techniques. These will be reported elsewhere while this paper is focused on the imaging part of the project. We introduce the system concept including design goals and constraints, and the individual components. We present the current state of the prototype development including first results.

  • 180. Nachtrab, F.
    et al.
    Hofmann, T.
    Speier, C.
    Lucic, J.
    Firsching, M.
    Uhlmann, N.
    Takman, P.
    Heinzl, C.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Krumm, M.
    Sauerwein, C.
    Development of a Timepix based detector for the NanoXCT project2015Inngår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, artikkel-id C11009Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The NanoXCT EU FP7 project [1] aims at developing a laboratory, i.e. bench top sized X-ray nano-CT system with a large field-of-view (FOV) for non-destructive testing needs in the micro- and nano-technology sector. The targeted voxel size is 50 nm at 0.175 mm FOV, the maximum FOV is 1 mm at 285 nm voxel size. Within the project a suitable X-ray source, detector and manipulation system have been developed. The system concept [2] omits the use of X-ray optics, to be able to provide a large FOV of up to 1 mm and to preserve the flexibility of state-of-the-art micro-CT systems. The targeted resolution will be reached via direct geometric magnification made possible by the development of a specialized high-flux nano-focus transmission X-ray tube. The end-user's demand for elemental analysis will be covered by energy-resolved measurement techniques, in particular a K-edge imaging method. Timepix [3] modules were chosen as the basis for the detector system, since a photon counting detector is advantageous for the long exposure times that come with very small focal spot sizes. Additional advantages are the small pixel size and adjustable energy threshold. To fulfill the requirements on field-of-view, a detector width > 3000 pixels was needed. The NanoXCT detector consists of four Hexa modules with 500 mu m silicon sensors supplied by X-ray Imaging Europe. An adapter board was developed to connect all four modules to one Fitpix3 readout. The final detector has an active area of 3072 x 512 pixels or approximately 17 x 3 cm(2). In this contribution we present the development of the Timepix based NanoXCT detector, it's application in the NanoXCT project for CT and material specific measurements and the current status of results.

  • 181.
    Nigicser, David
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Valerio, Turri
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Mårtensson, Jonas
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för industriell teknik och management (ITM), Centra, Integrated Transport Research Lab, ITRL.
    Arat, Mustafa Ali
    The Goodyear Rubber & Tire Company.
    Lima Simões da Silva, Eduardo
    DTU Space.
    Predictive Vehicle Motion Control for Post-Crash Scenarios2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an active safety system for passenger vehicles designed to mitigate secondary collisions after an initial impact. Thecontrol objective is to minimize lateral deviation from the known original path while achieving a safe heading angle after the initialcollision. A hierarchical controller architecture is proposed: the higher layer is formulated as a linear time-varying model predictivecontroller that defines the virtual control moment input; the lower layer deploys a rule-based controller that realizes the requestedmoment. The designed control system is tested and validated on a high-fidelity vehicle dynamics simulator.

  • 182. Nikkam, N.
    et al.
    Ghanbarpour, Morteza
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Khodabandeh, Rahmatollah
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Toprak, Muhammet S.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    The effect of particle size and base liquid on thermo-physical properties of ethylene and diethylene glycol based copper micro- and nanofluids2017Inngår i: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 86, s. 143-149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanofluid (NF) is a fluid containing nanometer-sized particles. The present work investigates, experimentally and theoretically, on fabrication and thermo-physical properties evaluation of ethylene glycol and diethylene glycol (EG/DEG) based nanofluids/microfluids (NFs/MFs) containing copper nanoparticles/microparticles (NPs/MPs) with focus on the effect of the particle size and the base liquid. A series of stable Cu NFs and MFs with various NP/MP concentration (1, 2 and 3 wt%) were fabricated by dispersing Cu NPs and Cu MPs in EG and DEG as the base liquids. The physicochemical properties of Cu NFs and MFs were analyzed by various techniques including X-Ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS). The thermo-physical properties including thermal conductivity (TC) and viscosity of EG/DEG based Cu NFs/MFs were measured at 20 to 40 °C. The results for TC and viscosity of EG based Cu NF/MFs were compared to the same NFs/MFs with DEG base liquid with focus on the impact of the particle size as well as the base liquid. The experiments showed that EG based NFs/MFs exhibit more favorable characteristics than that of DEG based ones. Moreover, NFs with Cu NPs revealed higher TC than those MFs containing Cu MPs at the same particle concentration and temperature (effect of NP size). As the best result, a TC enhancement of ~ 4.7% was achieved for EG based NF with 3 wt% Cu NP while maximum increase in viscosity of ~ 1.8% was observed for the same NF at 20 °C. To compare the experimental results with the estimated values, Maxwell predictive correlation and Corcione model were employed while Einstein equations as well as Kriger-Dougherty correlation were applied for TC and viscosity of NFs/MFs, respectively.

  • 183. Nikkam, N.
    et al.
    Toprak, Muhammet Sadaka
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fabrication and thermo-physical characterization of silver nanofluids: An experimental investigation on the effect of base liquid2018Inngår i: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 91, s. 196-200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanofluids (NFs) are solid-liquid composites prepared by stabilizing nanoparticles (NPs) in a base liquid, which is selected based on the technological area of application. For heat exchange applications the base liquid can be specified as water, ethylene glycol (EG), or their mixture. NFs have exhibited some potential to replace conventional heat transfer fluids due to enhancement of their thermal characteristics. The thermo-physical properties of NFs including thermal conductivity (TC) and viscosity may be affected by several factors including the base liquid, which is not well studied in the literature. Focus of the present work is to study the impact of base liquid by comparing the TC and viscosity of a commercial silver (Ag) NFs with lab-made water, EG and water/ethylene glycol (W/EG) mixture (50:50 by wt%) at different Ag NP loadings (1, 1.5 and 2 wt%). For this purpose, commercial water based Ag suspension (containing 1 wt% Ag NP) was acquired, which is used for the preparation of Ag NFs with different base liquids and NP loadings. Finally, the thermo-physical properties of NFs including TC and viscosity were measured and analyzed at 20 °C. The results revealed that W/EG based NFs containing 2 wt% Ag NP showed best performance with the highest TC enhancement of 12.4% and only 6.1% increase in viscosity, revealing that among different base liquids, W/EG based NFs are the most beneficial for heat transfer applications.

  • 184. Nikkam, Nader
    et al.
    Saleemi, Mohsin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Behi, Mohammadreza
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Khodabandeh, Rahmatollah
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Toprak, Muhammet S.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Experimental investigation on the effect of SiO2 secondary phase on thermo-physical properties of SiC nanofluids2017Inngår i: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 87, s. 164-168Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanofluids (NFs), wherein solid nanoparticles (NPs) are dispersed in traditional heat exchange fluids, are recognized for improving the performance of traditional fluids by enhancing their thermal conductivity (TC). The presence of impurities or undesired phases in commercial NPs may influence the thermo-physical properties of NFs including TC and viscosity, which makes it difficult to understand the real effect of NPs on heat transport characteristics of NFs. Moreover, the presence of these impurities in commercial NPs is unavoidable and their removal from commercial NPs with no negative impact on composition of NPs is challenging. To study the impact of impurities on thermo-physical properties of NFs a systematic experimental work was performed using commercial alpha-SiC and SiO2 NPs as the secondary phase as it commonly co-exists in commercial SiC batches. For this purpose, a series of NFs containing 9 wt% of alpha-SiC/SiO2 NP mixture with different content of SiO2 NPs from 5 to 50% were fabricated and investigated. The results show that as the undesired impurity phase (SiO2) increases, TC of NFs decreases slightly while viscosity increases dramatically. This may be a sound path to tuning the viscosity of the NFs while the achieved high TC is mildly influenced by the secondary phase.

  • 185.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Zone Plates for Hard X-Ray Free-Electron Lasers2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Hard x-ray free-electron lasers are novel sources of coherent x-rays with unprecedented brightness and very short pulses. The radiation from these sources enables a wide range of new experiments that were not possible with previous x-ray sources. Many of these experiments require the possibility to focus the intense x-ray beam onto small samples. This Thesis investigates the possibility to use diffractive zone plate optics to focus the radiation from hard x-ray free-electron lasers.

    The challenge for any optical element at free-electron laser sources is that the intensity in a single short pulses is high enough to potentially damage the optics. This is especially troublesome for zone plates, which are typically made of high Z elements that absorb a large part of the incident radiation. The first part of the Thesis is dedicated to simulations, where the temperature behavior of zone plates exposed to hard x-ray free-electron laser radiation is investigated. It is found that the temperature increase in a single pulse is several hundred Kelvin but still below the melting point of classical zone plate materials, such as gold, tungsten, and iridium.

    Even though the temperature increases are not high enough to melt a zone plate it is possible that stresses and strains caused by thermal expansion can damage the zone plate. This is first investigated in an experiment where tungsten gratings on diamond substrates are heated to high temperatures by a pulsed visible laser. It is found that the gratings are not damaged by the expected temperature fluctuations at free-electron lasers. Finally, a set of tungsten zone plates are tested at the Linac Coherent Light Source where they are exposed to a large number of pulses at varying fluence levels in a prefocused beam. Damage is only observed at fluence levels above those typically found in an unfocused x-ray free-electron laser beam. At higher fluences an alternative is to use a diamond zone plate, which has significantly less absorption and should be able to survive much higher fluence. Damage in diamond structures is investigated during the same experiment, but due to a remaining tungsten etch mask on top of the diamond the results are difficult to interpret.

    Additionally, we also demonstrate how the classical Ronchi test can be used to measure aberrations in focusing optics at an x-ray free-electron laser in a single pulse.

    The main result of this Thesis is that tungsten zone plates on diamond substrates can be used at hard x-ray free-electron laser sources.

  • 186.
    Nilsson, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Anders, Holmberg
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sinn, H.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Computer simulation of heat transfer in zone plate optics exposed to X-ray FEL radiation2011Inngår i: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 8077Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zone plates are circular diffraction gratings that can provide diffraction-limited nano-focusing of x-ray radiation. When designing zone plates for X-ray Free Electron Laser (XFEL) sources special attention has to be made concerning the high intensity of the sources. Absorption of x-rays in the zone material can lead to significant temperature increases in a single pulse and potentially destroy the zone plate. The zone plate might also be damaged as a result of temperature build up and/or temperature fluctuations on longer time scales. In this work we simulate the heat transfer in a zone plate on a substrate as it is exposed to XFEL radiation. This is done in a Finite Element Method model where each new x-ray pulse is treated as an instantaneous heat source and the temperature evolution between pulses is calculated by solving the heat equation. We use this model to simulate different zone plate and substrate designs and source parameters. Results for both the 8 keV source at LCLS and the 12.4 keV source at the European XFEL are presented. We simulate zone plates made of high Z metals such as gold, tungsten and iridium as well as zone plates made of low Z materials such as diamond. In the case of metal zone plates we investigate the influence of substrate material by comparing silicon and diamond substrates. We also study the effect of different cooling temperatures and cooling schemes. The results give valuable indications on the temperature behavior to expect and can serve as a basis for future experimental investigations of zone plates exposed to XFEL radiation.

  • 187.
    Nilsson, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sinn, H.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Simulation of heat transfer in zone plate optics irradiated by X-ray free electron laser radiation2010Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 621, nr 1-3, s. 620-626Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zone plates are high quality optics that have the potential to provide diffraction-limited nano-focusing of hard X-ray free electron laser radiation. The present publication investigates theoretically the temperature behavior of metal zone plates on a diamond substrate irradiated by 0.1 nm X-rays from the European X-ray Free Electron Laser. The heat transfer in the optic is simulated by solving the transient heat equation with the finite element method. Two different zone plate designs are considered, one small zone plate placed in the direct beam and one larger zone plate after the monochromator. The main result is that for all investigated cases the maximum temperature in the metal zone plate layer is at least a factor 2 below the melting point of the respective material, proving the efficiency of the proposed cooling scheme. However, zone plates in the direct beam experience large and rapid temperature fluctuations of several hundred Kelvin that might prove fatal to the optic. The situation is different for optics behind the monochromator with fluctuations in the 20 K range and maximum temperatures well below room temperature. The simulation results give valuable indications on the temperature behavior to be expected and are a basis for future experimental heat transfer and mechanical stability investigations of fabricated nanostructures.

  • 188.
    Nilsson, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sinn, H.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Zone Plates for Hard X-Ray FEL Radiation2011Inngår i: 10TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY / [ed] McNulty, I; Eyberger, C; Lai, B, American Institute of Physics (AIP), 2011, Vol. 1365, s. 120-123Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigated theoretically the use of zone plates for the focusing of the European X-ray Free Electron Laser (XFEL). In a finite-element simulation the heat load on zone plates placed in the high intensity x-ray beam was simulated for four different zone plate materials: gold, iridium, tungsten, and CVD diamond. The main result of the calculations is that all zone plates remain below the melting temperature throughout a full XFEL pulse train of 3000 pulses. However, if the zone plate is placed in the direct beam it will experience large and rapid temperature fluctuations on the order of 300 K. The situation is relaxed if the optic is placed behind a monochromator and the fluctuations are reduced to around 20 K. Besides heat load, the maximization of the total efficiency of the complete optical system is an important issue. We calculated the efficiency of different zone plates and monochromator systems and found that the final beam size of the XFEL in combination with its monochromaticity will be important parameters.

  • 189.
    Nilsson, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Schropp, A.
    Patommel, J.
    Hoppe, R.
    Seiboth, F.
    Meier, V.
    Schroer, C. G.
    Galtier, E.
    Nagler, B.
    Lee, H. J.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ronchi test for characterization of nanofocusing optics at a hard x-ray free-electron laser2012Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, nr 24, s. 5046-5048Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate the use of the classical Ronchi test to characterize aberrations in focusing optics at a hard x-ray free-electron laser. A grating is placed close to the focus and the interference between the different orders after the grating is observed in the far field. Any aberrations in the beam or the optics will distort the interference fringes. The methodis simple to implement and can provide single-shot information about the focusing quality. We used the Ronchi test to measure the aberrations in a nanofocusing Fresnel zone plate at the Linac Coherent Light Source at 8.194 keV.

  • 190.
    Nilsson, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sinn, H.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Thermal stability of tungsten zone plates for focusing hard x-ray free-electron laser radiation2012Inngår i: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 14, s. 043010-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Diffractive Fresnel zone plates made of tungsten show great promise for focusing hard x-ray free-electron laser (XFEL) radiation to very small spot sizes. However, they have to withstand the high-intensity pulses of the beam without being damaged. This might be problematic since each XFEL pulse will create a significant temperature increase in the zone plate nanostructures and it is therefore crucial that the optics are thermally stable, even for a large number of pulses. Here we have studied the thermal stability of tungsten zone-platelike nanostructures on diamond substrates using a pulsed Nd:YAG laser which creates temperature profiles similar to those expected from XFEL pulses. We found that the structures remained intact up to a laser fluence of 100 mJ cm(-2), corresponding to a 6 keV x-ray fluence of 590 mJ cm-2, which is above typical fluence levels in an unfocused XFEL beam. We have also performed an initial damage experiment at the LCLS hard XFEL facility at SLAC National Accelerator Laboratory, where a tungsten zone plate on a diamond substrate was exposed to 105 pulses of 6 keV x-rays with a pulse fluence of 350 mJ cm-2 without any damage occurring.

  • 191.
    Norlin, P.
    et al.
    Acreo AB, Kista, Sweden.
    Xu, C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Perttu, D.
    Silex Microsyst AB, Järfälla, Sweden.
    Lundqvist, M.
    Sectra Imtec AB, Solna, Sweden.
    Aslund, M.
    Sectra Imtec AB, Solna, Sweden.
    Bakowski, M.
    Acreo AB, Kista, Sweden.
    Evaluation of junction termination for silicon X-ray detectors2011Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 648, s. S68-S71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Junction terminations intended for silicon strip X-ray detectors were evaluated experimentally and with simulations, with respect to their tolerance to radiation-induced surface charge. The terminations were designed with an inner guard ring biased to the same potential as the active anode and multiple p+-doped rings with metallic field plates at floating potential. Two designs, one with 9 and one with 14 floating rings were evaluated and applied to simple non-segmented test diodes. The test diodes were irradiated with X-rays to 72-74 kGy, the surface charge was determined from capaciatance-voltage measurements, and reverse breakdown voltage was determined from I-V-curves. Both simulations and experiments showed superior performance of the 14-ring design. The experimentally determined surface charge density after irradiation was in the order of +5 x 10(11) cm(-2), and the breakdown voltages were similar to 900 and 1600 V for the 9-ring and 14-ring termination, respectively.

  • 192.
    Noroozi, Mohammad
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Linköping University, Sverige.
    Jayakumar, Ganesh
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektronik, Integrerade komponenter och kretsar.
    Zahmatkesh, Katayoun
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Lu, J.
    Hultman, L.
    Mensi, Mounir
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Marcinkevicius, Saulius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Hamawandi, Bejan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Yakhshi Tafti, Mohsen
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ergül, Adem
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ikonic, Z.
    Toprak, Muhammet
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Radamson, Henry H.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektronik, Integrerade komponenter och kretsar.
    Unprecedented thermoelectric power factor in SiGe nanowires field-effect transistors2017Inngår i: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 6, nr 9, s. Q114-Q119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, a novel CMOS compatible process for Si-based materials has been presented to form SiGe nanowires (NWs) on SiGe On Insulator (SGOI) wafers with unprecedented thermoelectric (TE) power factor (PF). The TE properties of SiGe NWs were characterized in a back-gate configuration and a physical model was applied to explain the experimental data. The carrier transport in NWs was modified by biasing voltage to the gate at different temperatures. The PF of SiGe NWs was enhanced by a factor of >2 in comparison with bulk SiGe over the temperature range of 273 K to 450 K. This enhancement is mainly attributed to the energy filtering of carriers in SiGe NWs, which were introduced by imperfections and defects created during condensation process to form SiGe layer or in NWs during the processing of NWs.

  • 193.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic Fluid and Cell Manipulation2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    During the last decade, ultrasonic manipulation has matured into an important tool with a wide range of applications, from fundamental cell biological research to clinical and industrial implementations. The contactless nature of ultrasound makes it possible to manipulate living cells in a gentle way, e.g., for positioning, sorting, and aggregation. However, when manipulating cells using ultrasound, especially using high acoustic amplitudes, a great deal of heat can be generated. This constitutes a challenge, since the viability of cells is dependent on a stable physiological temperature around 37°C.

         In this Thesis we present applications of ultrasonic manipulation of fluids, particles, and cells in temperature-controlled micrometer-sized devices fabricated using well established etching techniques, directly compatible with high-resolution fluorescence microscopy. Furthermore, we present ultrasonic manipulation in larger up to centimeter-sized devices optimized for fluid mixing and cell lysis. In the present work, two new ultrasonic manipulation platforms have been developed implementing temperature control. These platforms are much improved with increased performance and usability compared to previous platforms. Also, two new ultrasonic platforms utilizing low-frequency ultrasound for solubilization and cell lysis of microliter-volumed and milliliter-volumed samples have been designed and implemented.

         We have applied ultrasound to synchronize the interaction between large numbers of immune, natural killer cells, and cancer cells to study the cytotoxic response, on a single cell level. A heterogeneity was found among the natural killer cell population, i.e., some cells displayed high cytotoxic response while others were dormant. Furthermore, we have used temperature-controlled ultrasound to form up to 100, in parallel, solid cancer HepG2 tumors in a glass-silicon multi-well microplate. Next, we investigated the immune cells cytotoxic response against the solid tumors. We found a correlation between the number of immune cells compared to the size of the tumor and the cytotoxic outcome, i.e., if the tumor could be defeated.

                Finally, the effect of high acoustic pressure amplitudes in the MPa-range on cell viability has been studied in a newly developed platform optimized for long-term stable temperature control, independent on the applied ultrasound power. Lastly, we present two applications of ultrasonic fluid mixing and lysis of cells. One platform is optimized for small microliter-sized volumes in plastic disposable chips and another is optimized for large milliliter-sized volumes in plastic test tubes. The latter platform has been implemented for clinical sputum sample solubilization and cell lysis for genomic DNA extraction for subsequent pathogen detection

  • 194.
    Ohlin, Mathias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Influence of acoustic streaming on ultrasonic particle manipulation in a 100-well ring-transducer microplate2013Inngår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, nr 3, s. 035008-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We characterize and quantify the performance of ultrasonic particle aggregation and positioning in a 100-well microplate. We analyze the result when operating a planar ultrasonic ring transducer at different single actuation frequencies in the range 2.20-2.40 MHz, and compare with the result obtained from different schemes of frequency-modulated actuation. Compared to our previously used wedge transducer design, the ring transducer has a larger contact area facing the microplate, resulting in lower temperature increase for a given actuation voltage. Furthermore, we analyze the dynamics of acoustic streaming occurring simultaneously with the particle trapping in the wells of the microplate, and we define an adaptive ultrasonic actuation scheme for optimizing both efficiency and robustness of the method. The device is designed as a tool for ultrasound-mediated cell aggregation and positioning. This is a method for high-resolution optical characterization of time-dependent cellular processes at the level of single cells. In this paper, we demonstrate how to operate our device in order to optimize the scanning time of 3D confocal microscopy with the aim to perform high-resolution time-lapse imaging of cells or cell-cell interactions in a highly parallel manner.

  • 195.
    Ohlin, Mathias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Iranmanesh, Ida Sadat
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Temperature-controlled MPa-pressure ultrasonic cell manipulation in a microfluidic chip2015Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 15, nr 16, s. 3341-3349Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the temperature-independent impact on cell viability of relevant physical parameters during long-term, high-acoustic-pressure ultrasonic exposure in a microfluidic chip designed for ultrasonic-standing-wave trapping and aggregation of cells. We use a light-intensity method and 5 mum polymer beads for accurate acoustic pressure calibration before injecting cells into the device, and we monitor the viability of A549 lung cancer cells trapped during one hour in an ultrasonic standing wave with 1 MPa pressure amplitude. The microfluidic chip is actuated by a novel temperature-controlled ultrasonic transducer capable of keeping the temperature stable around 37 °C with an accuracy better than ±0.2 °C, independently on the ultrasonic power and heat produced by the system, thereby decoupling any temperature effect from other relevant effects on cells caused by the high-pressure acoustic field. We demonstrate that frequency-modulated ultrasonic actuation can produce acoustic pressures of equally high magnitudes as with single-frequency actuation, and we show that A549 lung cancer cells can be exposed to 1 MPa standing-wave acoustic pressure amplitudes for one hour without compromising cell viability. At this pressure level, we also measure the acoustic streaming induced around the trapped cell aggregate, and conclude that cell viability is not affected by streaming velocities of the order of 100 mum s(-1). Our results are important when implementing acoustophoresis methods in various clinical and biomedical applications.

  • 196.
    Ohlin, Mathias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Characterization of acoustic streaming in an ultrasonic cage2009Konferansepaper (Annet vitenskapelig)
  • 197.
    Olofsson, K.
    et al.
    KTH.
    Carannante, V.
    Frisk, T.
    KTH.
    Kushiro, K.
    Takai, M.
    Önfelt, B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellulär biofysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Unanchored micro-tumors in an ultrasonic actuated multi-well microplate with protein repellent coating2016Inngår i: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016, Chemical and Biological Microsystems Society , 2016, s. 409-410Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we demonstrate an improved tissue engineering method producing 100 three-dimensional (3D) HepG2 cell structures in parallel based on a combination of ultrasonic actuation and polymer coating in a multi-well microplate. By the use of a polymer coating in the plates, the method creates non-adherent tumor models of controlled size and shape which introduces both a more flexible 3D culture system as well as improved quality of the 3D tumor relative to previous studies [1].

  • 198.
    Olofsson, Karl
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Carannante, V.
    Karolinska Inst, Dept Microbiol Tumor & Cell Biol, Stockholm, Sweden..
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Kushiro, K.
    Univ Tokyo, Dept Bioengn, Tokyo, Japan..
    Takai, M.
    Univ Tokyo, Dept Bioengn, Tokyo, Japan..
    Lundqvist, A.
    Karolinska Inst, Dept Oncol Pathol, Stockholm, Sweden..
    Önfelt, Björn
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustic formation of multicellular tumor spheroids enabling on-chip functional and structural imaging2018Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 18, nr 16, s. 2466-2476Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Understanding the complex 3D tumor microenvironment is important in cancer research. This microenvironment can be modelled in vitro by culturing multicellular tumor spheroids (MCTS). Key challenges when using MCTS in applications such as high-throughput drug screening are overcoming imaging and analytical issues encountered during functional and structural investigations. To address these challenges, we use an ultrasonic standing wave (USW) based MCTS culture platform for parallel formation, staining and imaging of 100 whole MCTS. A protein repellent amphiphilic polymer coating enables flexible production of high quality and unanchored MCTS. This enables high-content multimode analysis based on flow cytometry and in situ optical microscopy. We use HepG2 hepatocellular carcinoma, A498 and ACHN renal carcinoma, and LUTC-2 thyroid carcinoma cell lines to demonstrate (i) the importance of the ultrasound-coating combination, (ii) bright field image based automatic characterization of MTCS, (iii) detailed deep tissue confocal imaging of whole MCTS mounted in a refractive index matching solution, and (iv) single cell functional analysis through flow cytometry of single cell suspensions of disintegrated MTCS. The USW MCTS culture platform is customizable and holds great potential for detailed multimode MCTS analysis in a high-content manner.

  • 199.
    Otendal, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    A Compact High-Brightness Liquid-Metal-Jet X-Ray Source2006Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis describes the development and characterization of a compact high-brightness liquid-metal-jet anode x-ray source. Initial calculations show that a source based on this concept could potentially lead to a >100-fold increase of the brightness compared to current state-of-the-art rotating-anode x-ray sources. This improvement is due to an increased thermal load capacity of the anode.

    A low-power proof-of-principle source has been built, and experiments show that the liquid-metal-jet anode can be operated at more than an order of magnitude higher power densities than modern solid-metal anodes. This brightness enhancement has been utilized to acquire in-line phase-contrast images of weakly absorbing objects with substantially shorter exposure times than previously reported. To be able to target different application areas different liquid-jet-anode materials have been tested. The Sn-jet anode could potentially be used in mammography examinations, whereas the Ga-jet could be utilized for, e.g., protein-structure determination with x-ray diffraction.

    Scaling to higher power and brightness levels is discussed and seems conceivable. A potential obstacle for further development of this source concept, the generation of a microscopic high-speed liquid-metal jet in vacuum, is investigated and is proven to be feasible. Dynamic-similarity experiments using water jets to simulate 30-μm, ~500-m/s tin and gallium jets show good coherence and directional stability of the jet. Other potential difficulties in the further source development, such as excessive debris emission and instabilities of the x-ray emission spot, are also investigated in some detail.

  • 200.
    Otendal, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hemberg, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Fysik. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Microscopic High-Speed Liquid-Metal Jets in Vacuum2005Inngår i: Experiments in Fluids, ISSN 0723-4864, E-ISSN 1432-1114, Vol. 39, s. 799-804Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a novel electron-impact x-ray source based on a high-speed liquid-metal-jet anode. Thermal power load calculations indicate that this new anode concept potentially could increase the achievable brightness in compact electron-impact x-ray sources by more than a factor 100 compared to current state-of-the-art rotating-anode or microfocus sources. A first, successful, low-power proof-of-principle experiment is described and the feasibility of scaling to high-brightness and high-power operation is discussed. Some possible applications that would benefit from such an increase in brightness are also briefly

1234567 151 - 200 of 352
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